There is an assumption that all the "sophomore" quarterbacks will take a big step forward this year, but NFL history indicates that it's unlikely. (Cam Newton is nodding somewhere.) We've talked about each player's incredible attributes plenty. But what are the biggest challenges facing each one?

Andrew Luck, Indianapolis Colts

Luck overcame a terrible offensive line last year by completing a number of low-percentage throws that few quarterbacks would even attempt. But those high-risk passes created a lot of turnovers. Indianapolis Colts general manager Ryan Grigson tried to address the problem in the offseason by signing right tackle Gosder Cherilus and guard Donald Thomas, but both players are risky bets. Luck will be asked to carry this team, especially his line.

Robert Griffin III, Washington Redskins

RGIII's biggest obstacle is almost too obvious to state. His torn ACL robbed him of an offseason of training and could remove some of his explosiveness as a runner early in the season. We'll be more interested to see Griffin's accuracy and ability to stand tall in the pocket.

When Tom Brady returned from his ACL injury, Brady's trademark pocket toughness and pinpoint accuracy were compromised. Griffin received a ton of attention last season for his big plays, but it was his "ball location" that stood out more than anything. Griffin delivered the ball exactly where it had to go as well as any quarterback in football. It will be tough to repeat that performance after his injury and missed offseason.

Wilson should be very good no matter what happens to his starting wide receivers. But Harvin and Rice are not a particularly reliable duo. It's a boom or bust combination.

Ryan Tannehill, Miami Dolphins

Tannehill has the most areas to improve on out of the group. While he displayed everything you'd want to see out of a young franchise quarterback, Tannehill was too inconsistent. He often missed routine passes, which rarely happened with the three quarterbacks above.

The Dolphins added Mike Wallace this offseason, but early reports about his chemistry with Tannehill haven't been great. The Dolphins are somewhat thin at wide receiver and have an inferior offensive line to a year ago. We like Lamar Miller's potential, but the running back group is unproven. Even if Tannehill improves, he needs more help from his teammates.

The entire team will have to withstand the pressure of higher expectations, especially if the team's offseason spending spree doesn't translate to early wins.